Drops have been noticed since the beginning of the 2010 breeding season.

"Probably what is more concerning is we are really not sure what contributing to that decline," Professor Bronwyn Gillanders of the School of Earth and Environmental Sciences said.

There were theories that the sudden fall in population could be part of the natural cycle for cephalopods, but due to the estimations carrying over several years, Professor Gillanders believed the fall in numbers could lead to more than a cyclic change.

"There's a range of biotic, like predator prey, interactions [and] abiotic things like temperature and other things that have been put forward as contributing to the decline, but at this stage there is nothing that jumps out."

Professor Gillanders also said a recent algal bloom and viral infection of dolphins was not likely to have contributed to the cuttlefish population decline.

Gathering data

Funded by the Fisheries Research Development Corporation, the study will focus on the movement, colonies, reproduction and sub-species of the animals.

The study will particularly focus in the Upper Spence Gulf, north of Wallaroo, where the species has been known to breed.

With breeding season beginning mid-May through to August and hatchings from September to November, researchers were hoping to receive data during the mating season.

Professor Gillanders said the university would be calling on recreational scuba divers and fishers to record any sightings or catching of giant cuttlefish on the community mapping website Redmap.

Contributors can mark where they found the cuttlefish, how many there were, and log other details like the sighting of eggs and juveniles.

"That will be critical to us trying to identify other potential, smaller aggregations."

Professor Gillanders also hoped to gather data on a theory that the Upper Spencer Gulf cuttlefish were a different species to the animals found in lower parts of the local waters.